The following abbreviations are used herein:    LAM: lipoarabinomannan    Et: endotoxin    BG: (1→3)-β-D-glucan.
A Limulus reagent (also called a lysate reagent) is a reagent containing a horseshoe crab amoebocyte lysate as a main component, and is used for the detection and measurement of Et and BG. Since the Limulus reagent has reactivity with Et and BG, when the Limulus reagent and the substances contact with one another, a cascade reaction in which various factors in the Limulus reagent are concerned (hereinafter, referred to as “Limulus reaction”) is induced, so these substances can be detected and measured by detecting this reaction.
On the other hand, it is known that LAM is a cell wall component specific to acid-fast bacteria (e.g., tubercle bacillus).
Patent Document 1 discloses an Et stabilizer containing an alkaline earth metal salt as an active ingredient and a method of assaying Et using the Et stabilizer. However, this document neither discloses nor teaches that the alkaline earth metal salt has an eliminating effect on the reactivity of LAM to a Limulus reagent.
Patent Document 2 discloses a method of assaying Et, which is characterized by treating plasma or blood serum with an aqueous solution of a mixture of calcium chloride and potassium hydroxide to prepare a specimen solution. However, the document neither discloses nor teaches that calcium chloride has an eliminating effect on the reactivity of LAM to a Limulus reagent.
In addition, a freeze-dried product of a Limulus reagent is typically dissolved in water, a specimen solution, a buffer, or the like and then used. However, there is no finding that the buffer has an eliminating effect on the reactivity of LAM to the Limulus reagent.
Further, Patent Document 3 describes a method of assaying a substance reactive to a Limulus reagent in a specimen using a Limulus reagent containing, as an active ingredient, a compound having a specific structure to show a buffer action and a horseshoe crab amoebocyte lysate. However, the document neither discloses nor teaches that the above compound has an eliminating effect on the reactivity of LAM to the Limulus reagent.
Patent Document 1: JP-A-8-75751
Patent Document 2: JP-A-4-136763
Patent document 3: JP-A-7-239332